(1) Field of the Invention
This invention relates to printing apparatus, and more particularly it is concerned with a serial printing apparatus of the impact-free type capable of effecting printing simultaneously on a plurality of sheets.
(2) Description of the Prior Art
Printing apparatus of the impact type known in the art suitable for effecting printing simultaneously on a plurality of pressure-sensitive sheets piled one over another include a printing apparatus of the matrix type system and a printing apparatus of the wire dot system. In these two systems of printing apparatus, a matrix type, a hammer or a wire serving as a printing member strikes a plurality of sheets with an impact and a force of impact generated by the printing member is transmitted to the sheets in one operation, to enable copying of the plurality of sheets to be effected. The greatest disadvantage this type of printing apparatus suffers is that the noise produced when the printing member strikes the sheets with an impact is great.
Meanwhile printing apparatus of the nonimpact type, such as ink jet printing apparatus, thermal printing apparatus and laser beam printing apparatus do not produce noise of impact. However, they suffer the disadvantage that it is impossible for them to effect printing simultaneously on a plurality of sheets.